My military ABU top has a pen sleeve on the left forearm. I carry my tactical pen there.

When I ride my motorcycle, it is accessible while my left hand is holding the clutch. Just to have something quick and handy. Preferably I'd be aware of my surroundings and not ride into trouble, but if something snuck up on me I'd have something to work with. In fact, with my helmet on, riding vest, riding gloves, I'd be pretty formidable hand-to-hand.